Recently, semiconductor components such as ICs have been highly integrated and have quickly become smaller in size. High-frequency components such as filters for use with semiconductor devices have also become smaller in size. Dielectric substrates made up of a plurality of dielectric layers are effective in making high-frequency components smaller in size (see, for example, Patent Documents 1 and 2).
Generally, it has been proposed to integrally combine a filter and an unbalanced-to-balanced converter in a dielectric substrate (see, for example, Patent Document 3).
Patent Document 1: Japanese Laid-Open Patent Publication No. 2002-280805
Patent Document 2: Japanese Laid-Open Patent Publication No. 2005-159512
Patent Document 3: Japanese Laid-Open Patent Publication No. 2004-056745